Christine Hunter

Baylor College of Medicine, Houston, TX, United States

Are you Christine Hunter?

Claim your profile

Publications (34)140.32 Total impact

  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Although tetrabenazine, a drug that depletes presynaptic dopamine by inhibiting vesicular monoamine transporter 2 (VMAT2), was approved by the U.S. Food and Drug Administration in 2008 for the treatment of chorea associated with Huntington's disease (HD), there is a paucity of data on its long-term efficacy and safety. Approximately 2,000 patients with a variety of hyperkinetic movement disorders had been treated with open-label tetrabenazine at the Movement Disorders Clinic, Baylor College of Medicine, since 1979. Tetrabenazine was usually started at 12.5 mg/day, and the dosage was gradually increased (up to 300 mg/day). Responses were rated by the investigator 1-5, with 1 = marked chorea reduction, excellent improvement in function; 2 = moderate chorea reduction, very good improvement in function; 3 = fair chorea improvement, only mild improvement in function; 4 = poor or no response for chorea and function; and 5 = worsening chorea, some functional deterioration. Efficacy and safety were analyzed retrospectively. By 2004, 98 HD chorea patients had received tetrabenazine for a mean of 3.1 years (range ≤1-11.4 years). Of those with valid ratings, 75% had either marked or very good responses (rating 1 or 2) at their optimal dosages. The most common adverse events occurring in ≥5% of the patients were somnolence (39%), insomnia (33%), depression (31%), accidental injury (26%), and dysphagia (19%). Efficacy and safety were comparable to results for non-HD chorea patients. Tetrabenazine treatment was associated with long-term improvement in chorea. Adverse event rates were comparable to those reported from controlled trials.
    Tremor and other hyperkinetic movements (New York, N.Y.). 01/2013; 3.
  • [show abstract] [hide abstract]
    ABSTRACT: Tetrabenazine is effective in the treatment of the chorea associated with Huntington disease and other hyperkinetic movement disorders. Following oral administration, tetrabenazine is hepatically transformed into 2 active metabolites that are CYP2D6 substrates. There are 4 CYP2D6 genotypes: poor metabolizers, intermediate metabolizers, extensive metabolizers, and ultrarapid metabolizers. CYP2D6 genotyping was performed on sequential subjects treated with tetrabenazine, but results were not known at the time of titration. Duration of titration to a stable dose, total daily dose, response rating scores, and adverse events were retrospectively collected and subsequently analyzed. Of 127 patients, the majority (n = 100) were categorized as extensive metabolizers, 14 as intermediate metabolizers, 11 as poor metabolizers, and 2 as ultrarapid metabolizers. Ultrarapid metabolizer patients needed a longer titration (8 vs 3.3, 4.4, and 3 weeks, respectively; P < .01) to achieve optimal benefit and required a higher average daily dose than the other patients, but this difference did not reach statistical significance. The treatment response was less robust in the intermediate metabolizer group when compared with the extensive metabolizer patients (P = .013), but there were no statistically significant differences between the various groups with regard to adverse effects. Our findings demonstrate that, aside from the need for a longer titration in the ultrarapid metabolizers, there are no distinguishing features of patients with various CYP2D6 genotypes, and therefore the current recommendation to systematically genotype all patients prescribed more than 50 mg/day of tetrabenazine should be reconsidered. © 2012 Movement Disorder Society.
    Movement Disorders 12/2012; · 4.56 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: To evaluate the efficacy and tolerability of lubiprostone (Amitiza) for constipation in Parkinson disease (PD) in a double-blind, randomized, controlled study. Patients with PD and clinically meaningful constipation (constipation rating scale score > 10 [range: 0-28]) were recruited from 2 academic movement disorder centers to participate in the study. After enrollment, patients were initially followed for 2 weeks and then were randomly assigned 1:1 to lubiprostone, and the dose was titrated up to 48 μg/day. They returned 4 weeks later for a final assessment. Data included stool diaries and global impressions (co-primary endpoints), demographics, Unified Parkinson's Disease Rating Scale scores, constipation scale scores, visual analog scale (VAS) scores, a stool diary, and adverse events. Fifty-four subjects (39 male, mean age 67.0 ± 10.1 years, and mean duration of PD 8.3 ± 5.4 years) were randomly assigned to lubiprostone or placebo. One patient in the drug group discontinued the study because of logistics, and one patient in the placebo group discontinued the study because of lack of efficacy. A marked or very marked clinical global improvement was reported by 16 of 25 (64.0%) subjects receiving drug vs 5 of 27 (18.5%) subjects receiving placebo (p = 0.001). The constipation rating scale (p < 0.05), VAS (p = 0.001), and stools per day in the diary (p < 0.001) all improved with drug compared with placebo. Adverse events with drug were mild, most commonly intermittent loose stools. In this randomized controlled trial, lubiprostone seemed to be well tolerated and effective for the short-term treatment of constipation in PD.
    Neurology 05/2012; 78(21):1650-4. · 8.25 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Apomorphine injections effectively abort "off" episodes in Parkinson's disease (PD). However, their use is limited by actual and perceived adverse events (AE). To our knowledge, no study has evaluated for predictors of these problems. To assess predictors of initial common AE and long-term tolerability of apomorphine injections in PD. We prospectively monitored for AE in 28 consecutive PD patients receiving initial apomorphine injections. Sequential visual analogue scale scores for nausea and in standing systolic blood pressure drops at baseline (mean of 2 assessments), 10, 20, and 40 min post-injection were acquired. Assessed historic variables included patient demographics and clinical data, treatment histories, previous AE to other dopaminergic treatments and whether patients received the recommended three day pre-treatment dose of trimethobenzamide. We also correlated the L-dopa equivalent doses with apomorphine dose needed to turn "on". No patient demographic or previous history of dopaminergic AE predicted nausea, except for baseline pre-injection nausea that day at baseline. Three days of trimethobenzamide, as recommended, was actually associated with more nausea than a single dose or no dose, even though a lack of association after matched analysis was found. A younger patient age was associated with hypotension. L-dopa equivalent dose modestly correlated with final apomorphine dose to turn "on". A previous history of nausea and hypotension, and older age should not dissuade a trial of apomorphine if clinically justified. A three day pre-treatment dose of trimethobenzamide, as recommended in the United States, does not reduce nausea.
    Parkinsonism & Related Disorders 01/2012; 18(5):619-22. · 3.27 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Selegiline is a monoamine-B specific inhibitor used to treat Parkinson's disease. A Zydis sublingual preparation has more efficient absorption and less first pass amphetamine metabolites. We conducted an open label oral to Zydis switch study to evaluate tolerability of rapid switch, and relative efficacy, in 48 subjects from 5 sites. Overall patients preferred the Zydis preparation. Per clinician global impressions, fluctuations improved and the "on" UPDRS part II scores improved. Total UPDRS and measures of fatigue and sleep were unchanged. Adverse events were mild. Patients generally preferred the Zydis selegiline preparation but the modest difference is of unclear clinical significance given the open label nature of the trial.
    Parkinsonism & Related Disorders 11/2010; 17(2):117-8. · 3.27 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Advanced Parkinson's disease (PD) is associated with various motor and non-motor symptoms which adversely impact health-related quality of life (HRQoL). Subthalamic nucleus (STN) deep brain stimulation (DBS) has been reported to improve some dimensions of HRQoL in appropriately selected candidates. Prior studies of HRQoL following DBS have used instruments comprising a predetermined list of questions which assess issues that are generally relevant in PD, but that may not be of equal or consistent importance to all individuals. In this study, we evaluate the effect of STN DBS on quality of life using the QLS(M), a modular questionnaire in which satisfaction scores for each item are weighted in light of patient-rated importance. We prospectively analysed QLS(M) scores in 21 patients with PD (11 men, mean age 61.5+/-8.6 years) before STN DBS surgery and at a mean 7.4+/-1.5, and again at a mean 16.6+/-6.8 months postoperatively. Following STN DBS, patients experienced an improvement in HRQoL as measured by various items of the movement disorder and health modules of the QLS(M). Specifically, QLS(M) items pertaining to energy level/enjoyment of life, independence from help, controllability/fluidity of movement and steadiness when standing and walking showed significant improvements, although items concerning general life issues (eg, occupational function, interpersonal relationships, leisure activities) did not improve. Following STN DBS, symptomatic and functional improvements translate into higher HRQoL, with high satisfaction in domains related to movement disorders and general health.
    Journal of neurology, neurosurgery, and psychiatry 10/2009; 81(3):315-9. · 4.87 Impact Factor
  • Source
    The Journal of Clinical Pharmacology 04/2008; 48(3):379-84. · 2.84 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: In contrast to essential tremor (ET), psychogenic tremor (PT) is often manifested by shaking with variable amplitude and frequency, distractibility, suggestibility, and entrainment. The sensitivity and specificity of these findings in differentiating PT and ET have not been systematically examined. In order to determine clinical features that reliably distinguish PT from ET, we collected patient information regarding tremor onset, spontaneous remissions, family history, and employment history. A "blinded" rater evaluated video segments of subjects using a standardized protocol with special attention to distractibility, suggestibility, or entrainment. A total of 45 subjects with ET or PT were enrolled in this study: 33 met clinical criteria for ET with a mean age of 56.8+/-17.0 years and 12 met clinical criteria for PT with a mean age of 42.5+/-11.0 years. PT subjects were significantly more likely to relay a history of sudden onset (p=0.03), spontaneous remissions (p=0.03), and shorter duration of tremor (p=0.001). Family history of tremor was significantly more common in the ET group (p=0.001). A moderate-to-marked degree of distraction with alternate finger tapping (p=0.01) and mental concentration on serial 7 s (p=0.01) was more common in PT. Furthermore, suggestibility with a tuning fork (p=0.04) and exacerbation with hyperventilation (p=0.06) seemed predictive of PT. Entrainment was not different in the two groups. In conclusion, a history of tremor with sudden onset and spontaneous remissions along with distractibility and suggestibility on examination are good predictors of PT and help differentiate it from ET.
    Journal of the Neurological Sciences 01/2008; 263(1-2):94-9. · 2.24 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: To assess tetrabenazine (TBZ) efficacy by evaluating the change in Huntington disease-associated chorea resulting from TBZ treatment withdrawal. Thirty patients treated in the long term were randomized to 1 of 3 groups assigned to withdraw from TBZ in a double-blind, staggered fashion during a 5-day period. The chorea scores of subjects withdrawn from TBZ treatment increased by 5.3 units from days 1 to 3, whereas the scores of the group with partial or no withdrawal of TBZ treatment increased by 3.0 units (P = 0.0773). A post hoc analysis of the linear trend was positive for reemergent chorea (P = 0.0486). No serious adverse events were reported after abrupt withdrawal of TBZ treatment. The trend for reemergence of chorea in patients with Huntington disease who were withdrawn from TBZ treatment is consistent with the findings from previous studies, thus showing the effectiveness of TBZ in reducing chorea.
    Clinical neuropharmacology 01/2008; 31(3):127-33. · 2.35 Impact Factor
  • Source
    William G Ondo, Nicte I Mejia, Christine B Hunter
    Parkinsonism & Related Disorders 11/2007; 13(7):453-4. · 3.27 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The object of this study was to assess the long-term safety of deep brain stimulation (DBS) in a large population of patients with a variety of movement disorders. All patients treated with DBS at the authors' center between 1995 and 2005 were assessed for intraoperative, perioperative, and long-term adverse events (AEs). A total of 319 patients underwent DBS device implantation. Of these 319, 182 suffered from medically refractory Parkinson disease; the other patients had essential tremor (112 patients), dystonia (19 patients), and other hyperkinetic movement disorders (six patients). Intraoperative AEs were rare and included vasovagal response in eight patients (2.5%), syncope in four (1.2%), severe cough in three (0.9%), transient ischemic attack in one (0.3%), arrhythmia in one (0.3%), and confusion in one (0.3%). Perioperative AEs included headache in 48 patients (15.0%), confusion in 16 (5.0%), and hallucinations in nine (2.8%). Serious intraoperative/perioperative AEs included isolated seizure in four patients (1.2%), intracerebral hemorrhage in two patients (0.6%), intraventricular hemorrhage in two patients (0.6%), and a large subdural hematoma in one patient (0.3%). Persistent long-term complications of DBS surgery included dysarthria (4.0%), worsening gait (3.8%), cognitive dysfunction (4.0%), and infection (4.4%). Revisions were completed in 25 patients (7.8%) for the following reasons: loss of effect, lack of efficacy, infection, lead fracture, and lead migration. Hardware-related complications included 12 lead fractures and 10 lead migrations. The authors conclude that in their 10-year experience, DBS has proven to be safe for the treatment of medically refractory movement disorders.
    Journal of Neurosurgery 05/2007; 106(4):621-5. · 3.15 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Mutations in the parkin gene cause autosomal recessive early-onset Parkinson disease (EOPD). The A265G variant in the HS1 binding protein 3 gene (HS1BP3) is common in essential tremor (ET). To investigate the presence of mutations in the parkin gene and the A265G variant in the HS1BP3 gene in a Mexican family with EOPD, ET, and Bell palsy. Direct sequencing, semiquantitative polymerase chain reaction, and reverse transcription-polymerase chain reaction were performed in the 14 members of this family. Mexican family. Patients Two patients with EOPD were analyzed. Compound heterozygous mutations (EX 3_6 del and EX 5 del) in the parkin gene were identified in 2 patients with EOPD, characterized by beneficial response to levodopa, relatively slow progression, and motor complications. Although heterozygous EX 3_6 del and homozygous EX 5 del mutations in the parkin gene have been previously described, to our knowledge, this is the first report of these mutations in compound heterozygotes. Seven heterozygous A265G variants in the HS1BP3 gene were found in this pedigree, but they did not cosegregate with ET, Parkinson disease, or Bell palsy, supporting the conclusion that this variant is not associated with ET. Compound heterozygous parkin mutations (EX 3_6 del and EX 5 del) caused EOPD in this family, but the A265G variant in the HS1BP3 gene, previously considered to be responsible for ET, was probably not pathogenically related to the ET in this family.
    JAMA Neurology 04/2007; 64(3):421-4. · 7.58 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: We sought to assess the short-term clinical effects of tetrabenazine (TBZ) on choreic movements in Huntington's disease patients. A total of 10 patients on stable doses of TBZ were enrolled in this observational study. Patients took their evening dose of TBZ and presented the next day to the Baylor College of Medicine Movement Disorders Clinic without taking the usual morning dose. They were assessed using the Unified Huntington's Disease Rating Scale (UHDRS) motor assessment and Beck Depression Inventory. The usual morning dose of TBZ was then administered and patients were followed with serial UHDRS motor examinations approximately every 2 hours until choreic movements subsided and then returned. TBZ decreased the UHDRS chorea score on average 42.4% +/- 17.8%. The duration of effect varied from a minimum of 3.2 hours to a maximum of 8.1 hours (mean = 5.4 +/- 1.3). No patient experienced an adverse event related to TBZ or its withdrawal. During short-term follow-up after a single dose, TBZ improves chorea for approximately 5 hours.
    Movement Disorders 02/2007; 22(1):10-3. · 4.56 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: In this multicenter study of 100 patients with cervical dystonia, we examined the immunogenicity of botulinum toxin type B (BTX-B) and correlated the clinical response with the presence of blocking antibodies (Abs) using a novel mouse protection assay. One-third of the patients who were negative for BTX-B Abs at baseline became positive for BTX-B Abs at last visit. Thus, the high antigenicity of BTX-B limits its long-term efficacy.
    Neurology 01/2007; 67(12):2233-5. · 8.25 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Recent discoveries of disease-causing genes in Parkinson's disease (PD) have generated considerable interest regarding genetic testing in PD. The attitudes toward genetic testing are largely influenced by knowledge and preconceived notions. We investigated the relationship between knowledge of and attitude towards predictive genetic testing of PD in two independent centers in America and Asia involving PD patients and caregivers. In a prospective study involving 515 subjects comprising of PD patients and their caregivers in two independent centers in America and Asia, the level of knowledge about genetic testing and patients' attitudes towards such testing were evaluated using a standardized questionnaire. American PD patients had a higher level of knowledge of PD genetics than Asian PD (31.1% vs. 12.3%, p=0.0002). A greater number of American PD patients and caregivers reported a positive attitude towards the potential medical benefits of genetic testing compared to their Asian counterparts (85.4% vs. 42.2%, 92.2% vs. 32.1%, p<0.00005), but a more negative attitude towards potential compromise in getting health and life insurance (43.7% vs. 25.8%, p=0.0002). However, in the Asian cohort, multivariate analysis revealed that a high level of genetics knowledge was associated with a positive attitude response regarding the potential medical benefits of testing (p<0.0005), but a negative attitude towards compromises in healthcare and life insurance, getting a job and starting a family (p<0.0005). These associations were not observed amongst American subjects. The relationship between level of genetic knowledge and attitude towards potential risks and benefits of predictive genetic testing in PD was distinctly different in two independent, racially and culturally different PD populations and caregivers. These observations have clinical implications in the development of PD genetic counseling programs.
    Journal of the Neurological Sciences 01/2007; 252(2):113-20. · 2.24 Impact Factor
  • Christopher Kenney, Christine Hunter, Joseph Jankovic
    [show abstract] [hide abstract]
    ABSTRACT: We sought to review the long-term tolerability of tetrabenazine (TBZ) and seek determinants of tolerability in the treatment of hyperkinetic movement disorders. A retrospective chart review was performed on patients treated with TBZ between 1997 and 2004. Efficacy of TBZ was assessed by a 1- to 5-point response scale (1 = marked reduction in abnormal movements, 5 = worsening). All adverse events (AEs) were captured according to their relationship with study drug. A total of 448 patients (42% male) were treated for a variety of hyperkinesias, including tardive dyskinesia (n = 149), dystonia (n = 132), chorea (n = 98), tics (n = 92), and myoclonus (n = 19). The mean age at onset of the movement disorder was 43.0 +/- 24.2 years, with TBZ starting at a mean age of 50.0 +/- 22.3 years. Patients remained on treatment for a mean of 2.3 +/- 3.4 years. An efficacy response rating of 1 or 2 was sustained in the majority of patients between the first and last visit. Common AEs included drowsiness (25.0%), Parkinsonism (15.4%), depression (7.6%), and akathisia (7.6%). Comparison of log-likelihood ratios revealed that age was a reliable predictor of Parkinsonism (P < 0.0001). TBZ is a safe and effective drug for the long-term treatment of hyperkinetic movement disorders.
    Movement Disorders 01/2007; 22(2):193-7. · 4.56 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Mutations in the leucine-rich repeat kinase-2 gene (LRRK2) are responsible for some forms of familial as well as sporadic Parkinson's disease (PD). The purpose of this study was to examine the frequency of a single pathogenic mutation (6055G > A) in the kinase domain of this gene in United States and Tunisian familial PD and to compare clinical characteristics between patients with and without the mutation. Standardized case report forms were used for clinical and demographic data collection. We investigated the frequency of the most common substitution of LRRK2 (G2019S, 6055G>A) and its impact on epidemiological and phenotypic features. The frequency of mutations in Tunisian families was 42% (38/91) and in U.S. families 2.6% (1/39), with the unique opportunity to compare homozygous (n = 23) and heterozygous (n = 109) Tunisian carriers of G2019S substitutions. Individuals with G2019S substitutions had an older age at onset but few other differences compared with families negative for the substitution. Patients with LRRK2 mutations had typical clinical features of PD. Comparisons between individuals with heterozygous and homozygous LRRK2 mutations suggested that gene dosage was not correlated with phenotypic differences; however, the estimated penetrance was greater in homozygotes across all age groups.
    Movement Disorders 01/2007; 22(1):55-61. · 4.56 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: In addition to the G2019S mutation in the leucine-rich repeat kinase 2 gene (LRRK2), which is particularly frequent in patients of Ashkenazi Jewish and Northern African origin, three amino acid substitutions (R1441C, R1441G, and R1441H), all at the same residue (R1441), have been identified as important genetic causes of Parkinson disease (PD). To evaluate the frequency of R1441C/G/H and G2019S mutations in the LRRK2 gene in North American patients with PD and to explore genotype-phenotype correlations, we screened 496 PD patients from North America. One Hispanic female was heterozygous for the LRRK2 R1441G mutation, and six other cases including 2 non-Jewish/non-Hispanic whites, 3 Ashkenazi Jewish, and 1 Hispanic, were found to be heterozygous for the LRRK2 G2019S mutation. G2019S mutation in the LRRK2 gene is a common mutation associated with PD in a North American population, especially in Jewish PD patients (10.7%), while the R1441C/G/H mutation occurs at a relatively low frequency in North Americans except possibly in Hispanics for R1441G. All six G2019S carriers shared a common haplotype with that observed in Europeans and North Africans. The clinical features of all seven cases with LRRK2 mutation were quite broad and included early and late disease onset. These finding may provide new insights into the cause and diagnosis of PD and have implications for genetic counseling.
    Journal of the Neurological Sciences 01/2007; 251(1-2):102-6. · 2.24 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Mutations in the parkin gene (PRKN) cause autosomal recessive early-onset Parkinson disease (EOPD). To investigate the presence of mutations in the PRKN gene in a white family with EOPD and the genotype-phenotype correlations. Twenty members belonging to 3 generations of the EOPD family with 4 affected subjects underwent genetic analysis. Direct genomic DNA sequencing, semiquantitative polymerase chain reaction, real-time quantitative polymerase chain reaction, and reverse-transcriptase polymerase chain reaction analyses were performed to identify the PRKN mutation. Compound heterozygous mutations (T240M and EX 5_6 del) in the PRKN gene were identified in 4 patients with early onset (at ages 30-38 years). Although heterozygous T240M and homozygous EX 5_6 del mutations in the PRKN gene have been previously described, this is, to our knowledge, the first report of these mutations in compound heterozygotes. The phenotype of patients was that of classic autosomal recessive EOPD characterized by beneficial response to levodopa, relatively slow progression, and motor complications. All heterozygous mutation carriers (T240M or EX 5_6 del) and a 56-year-old woman who was a compound heterozygous mutation carrier (T240M and EX 5_6 del) were free of any neurological symptoms. Compound heterozygous mutations (T240M and EX 5_6 del) in the PRKN gene were found to cause autosomal recessive EOPD in 4 members of a large white family. One additional member with the same mutation, who is more than 10 years older than the mean age at onset of the 4 affected individuals, had no clinical manifestation of the disease. This incomplete penetrance has implications for genetic counseling, and it suggests that complex gene-environment interactions may play a role in the pathogenesis of PRKN EOPD.
    JAMA Neurology 03/2006; 63(2):273-7. · 7.58 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: To determine whether a history of depression predisposes hyperkinetic patients treated with tetrabenazine (TBZ) to a recurrence or worsening of this symptom. We retrospectively reviewed the charts of 518 patients treated with TBZ to determine the frequency of depression and other adverse events. Charts were screened for the preexistence, development, or exacerbation of depression during the course of treatment. The most common adverse events related to TBZ were somnolence (27.4%), depression (15.1%), parkinsonism (11.8%), and akathisia (8.9%); 78 patients (15.1%) experienced depression for the first time or an exacerbation of existing depression. Of those patients with no history of depression, 28 (11.4%) of 246 were newly diagnosed with depression. Patients with a documented history of depression experienced a significantly higher rate of worsening in 50 (18.4%) of 272 cases (P = 0.03). However, patients with a history of depression experienced more improvement of their hyperkinesia compared to those without a history of depression (P < 0.01). Depression, an adverse event of TBZ, is more likely to occur or worsen in patients with a preexisting history of depression.
    Clinical Neuropharmacology 01/2006; 29(5):259-64. · 1.82 Impact Factor

Publication Stats

795 Citations
140.32 Total Impact Points

Institutions

  • 1999–2009
    • Baylor College of Medicine
      • Department of Neurology
      Houston, TX, United States
  • 2008
    • Boston University
      • Department of Neurology
      Boston, MA, United States
  • 2007
    • Singapore General Hospital
      • Department of Neurology
      Tumasik, Singapore